[SCSI] qla1280: Fix queue depth problem
The qla1280 driver was ANDing the output value of mailbox register
0 with (1 << target-number) to determine whether to enable queueing
on the target in question.
But mailbox register 0 has the status code for the mailbox command
(in this case, Set Target Parameters). Potential values are:
/*
* ISP mailbox command complete status codes
*/
So clearly that is in error. I can't think what the author of that
line was looking for in a mailbox register, so I just eliminated the
AND. flag is used later in the function, and I think that the later
usage was also wrong, though it was used to set values that aren't
used. Oh well, an overhaul of this driver is not what I want to do
now -- just a bugfix.
After the fix, I found that my disks were getting a queue depth of
255, which is far too many. Most SCSI disks are limited to 32 or
64. In any case, there's no point, queueing up a bunch of commands
to the adapter that will just result in queue full or starve other
targets from being issued commands due to running out of internal
memory. So I dropped default queue depth to 32 (from which 1 is
subtracted elsewhere, giving net of 31).
I tested with a Seagate ST336753LC, and results look good, so
I'm satisfied with this patch.
Signed-off-by: Jeremy Higdon <jeremy@sgi.com>
Acked-by: Jes Sorensen <jes@sgi.com>
Cc: Stable Tree <stable@kernel.org>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
1 file changed